U.S. patent application number 10/025977 was filed with the patent office on 2003-06-26 for devices and methods of repairing cardiac valves.
Invention is credited to Burdulis, Albert, Shennib, Hani.
Application Number | 20030120341 10/025977 |
Document ID | / |
Family ID | 21829120 |
Filed Date | 2003-06-26 |
United States Patent
Application |
20030120341 |
Kind Code |
A1 |
Shennib, Hani ; et
al. |
June 26, 2003 |
Devices and methods of repairing cardiac valves
Abstract
Devices and methods are provided for securing leaflets of a
cardiac valve together. The subject devices include an assembly
having a fastener, means for temporarily securing the fastener to
the leaflets and means for permanently securing the fastener to the
leaflets and means for anchoring the fastener to the heart wall.
The subject methods are characterized by temporarily grasping the
leaflets of a valve together at an apposition point, assessing at
least one of blood flow and pressure gradient across said valve,
determining whether to permanently secure the valve leaflets at
said selected apposition point based upon at least one of the
measured blood flow and pressure gradient, and performing one of
permanently attaching the leaflets together at the apposition site
or releasing the grasped leaflets. Also included are assemblies
which include a subject device and a delivery device and may
include a pressure monitoring member and/or a flow monitoring
member. Kits which include the subject devices are also
provided.
Inventors: |
Shennib, Hani; (Mt. Royal,
CA) ; Burdulis, Albert; (San Francisco, CA) |
Correspondence
Address: |
BOZICEVIC, FIELD & FRANCIS LLP
200 MIDDLEFIELD RD
SUITE 200
MENLO PARK
CA
94025
US
|
Family ID: |
21829120 |
Appl. No.: |
10/025977 |
Filed: |
December 21, 2001 |
Current U.S.
Class: |
623/2.12 ;
623/904 |
Current CPC
Class: |
A61B 2017/00685
20130101; A61B 2017/0417 20130101; A61B 2017/0404 20130101; A61B
5/0215 20130101; A61F 2/2457 20130101; A61B 2017/00243 20130101;
A61B 17/122 20130101; A61B 2017/00783 20130101 |
Class at
Publication: |
623/2.12 ;
623/904 |
International
Class: |
A61F 002/24 |
Claims
What is claimed is:
1. An assembly for securing leaflets of a cardiac valve together at
a point of apposition between the valve leaflets, said assembly
comprising: a fastener; a means for temporarily securing said
fastener to said leaflets; and a means for permanently securing
said fastener to said leaflets.
2. The assembly according to claim 1, further comprising a delivery
sheath for delivering said fastener from outside a patient's body
to said valve leaflets.
3. The assembly according to claim 2, wherein said sheath is
selected from the group consisting of a catheter and a cannula.
4. The assembly according to claim 1, wherein said assembly further
includes at least one of a pressure monitoring probe and a flow
monitoring probe.
5. The assembly according to claim 4, wherein at least one of said
pressure monitoring probe and said flow monitoring probe is
configured to be delivered through a lumen of said delivery
sheath.
6. The assembly according to claim 2, wherein said delivery sheath
comprises said means for temporarily securing said fastener to said
leaflets.
7. The assembly according to claim 2 wherein said fastener
comprises said means for permanently securing said fastener to said
leaflets.
8. The assembly according to claim 1 further comprising an
anchoring mechanism attached to said fastener.
9. A method for securing together leaflets of a cardiac valve of a
heart having an apex, said method comprising: (a) temporarily
grasping the leaflets of a valve together at a selected apposition
point; (b) measuring at least one of blood flow and pressure
gradient across said valve; (c) determining whether to permanently
secure said valve leaflets at said selected apposition point based
upon at least one of said measured blood flow and pressure
gradient; and (d) performing one of permanently securing said
leaflets together at said selected apposition site or releasing
said grasped leaflets.
10. The method according to claim 9, further comprising, prior to
said step (a), measuring one of at least blood flow and pressure
gradient across said valve to obtain a baseline measurement(s).
11. The method according to claim 10, wherein step (c) comprises
comparing said measurement(s) of step (b) with said baseline
measurement(s).
12. The method according to claim 9, further comprising repeating
said steps (a) through (d).
13. The method according to claim 12, wherein said steps (a)
through (d) are repeated until the measurement(s) of step (b)
indicates that the functioning of said valve leaflets is
sufficiently improved.
14. The method according to claim 9 wherein said method is
performed using the assembly of claim 1.
15. The method according to claim 9 wherein said method is
performed by means of an endovascular approach.
16. The method according to claim 9 wherein said method is
performed by means of a surgical approach.
17. The method according to claim 16 further comprising accessing
said cardiac valve through an entry site formed within the apex of
the heart.
18. The method according to claim 9 wherein said method is
performed while the heart is beating.
19. A method for repairing a regurgitating cardiac valve having at
least two opposing leaflets, said method comprising: (a) providing
the assembly of claim 1; (b) delivering said fastener to said
leaflets; (c) selecting a point of apposition between said
leaflets; (d) temporarily causing said fastener to grasp said
leaflets at said selected point of apposition; and (e) assessing at
least one of blood flow and pressure gradient across said leaflets;
and (f) determining whether to permanently secure said fastener to
said leaflets at said selected apposition point based upon at least
one of said assessed blood flow and pressure gradient.
20. The method according to claim 19, upon determining not to
permanently secure said fastener to said leaflets at said selected
apposition point, further comprising: (g) causing said fastener to
release said grasped leaflets; (h) selecting a second point of
apposition between said leaflets; (i) repeating steps (d), (e) and
(f).
21. The method according to claim 19, further comprising: (g)
permanently securing said leaflets together at said selected
apposition site.
22. The method according to claim 21, further comprising: (h)
repeating steps (a) through (f) for one or more additional selected
apposition sites.
23. The method according to claim 21, further comprising: (h)
anchoring said fastener to a location on the cardiac anatomy.
24. The method according to claim 23, wherein said fastener is
anchored to the ventricle wall.
25. The method according to claim 19, wherein said steps (b), (c)
and (d) are performed with the assistance of transesophageal
echocardiogram.
26. The method according to claim 19, wherein said blood flow is
assessed by means of transesophageal echocardiogram.
27. A kit for repairing a cardiac valve, said kit comprising; an
assembly according to claim 1; and a plurality of said
fasteners.
28. The kit according to claim 27 further comprising a fastener
delivery sheath configured for endovascularly delivering said
fastener to said cardiac valve.
29. The kit according to claim 27 further comprising a fastener
delivery sheath configured for delivering said fastener to said
cardiac valve through a surgical opening within the chest cavity of
a patient.
Description
FIELD OF THE INVENTION
[0001] The invention relates to devices and methods for the less
invasive repair of cardiac valves, and particularly to less
invasive repair of mitral and tricuspid valves.
BACKGROUND OF THE INVENTION
[0002] The human heart has four valves; the aortic valve, the
mitral valve, the pulmonary valve and the tricuspid valve. Various
diseases and certain genetic defects of the heart valves can impair
the proper functioning of the valves. Improper functioning of a
valve can be severely debilitating and even fatal if left
untreated, particularly if the diseased valve is the aortic valve
(between the left ventricle and the aorta) or the mitral valve
(between the left atrium and left ventricle). The common defects
and diseases affecting each of these valves, and the treatments
thereof, are typically different.
[0003] The aortic valve and, infrequently, the pulmonary valve, are
prone to stenosis. Stenosis typically involves the buildup of
calcified material on the valve leaflets, causing them to thicken
and impairing their ability to fully open to permit adequate
forward blood flow. Because stenotic damaged sustained by leaflets
is irreversible, the most conventional treatment for stenotic
aortic and pulmonic valves is the removal and replacement of the
diseased valve.
[0004] On the other hand, the mitral valve and, less frequently,
the tricuspid valve, are more prone to deformation, such as
dilation of the valve annulus, tearing of the chordae tendinae and
leaflet prolapse, which results in valvular insufficiency wherein
the valve does not close properly and allows for regurgitation or
back flow from the left ventricle into the left atrium.
Deformations in the structure or shape of the mitral or tricuspid
valve are repairable. Thus, because prosthetic valves have certain
disadvantages that can have serious effects (e.g., mechanical
valves carry the risk of thromboembolism and require
anticoagulation treatment, and biological valves have limited
durability), an improper functioning mitral or tricuspid valve is
ideally repaired rather than replaced.
[0005] The mitral valve includes two leaflets or cusps, called the
anterior and posterior leaflets, which are encircled by a dense
fibrous ring of tissue known as the annulus. The leaflets are of
unequal size with the posterior leaflet having a wider attachment
area to the annulus. The end of the lines at which the leaflets
come together are called the commissures. The leaflets are held in
place by the chordae or threads connected at the base by two
papillary muscles which extend from the underside of the leaflets
to the papillary muscles within the wall of the left ventricle. The
annulus of a normal mitral valve is somewhat "D" shaped.
[0006] The tricuspid valve, also an atrioventricular valve,
functions similarly to the mitral valve but has three leaflets
rather than two. The three leaflets, referred to as the anterior,
posterior, and septal leaflets, and are roughly triangular in
shape. Like the mitral valve leaflets, the tricuspid valve leaflets
are encircled by a fibrous annulus and are held in place by chordae
connected to associated papillary muscles. The annulus of the
tricuspid valve is more nearly circular than is the mitral valve.
While the two valves function very similarly, the mitral valve is
subject to significantly higher back pressure than is the tricuspid
valve and, as such, the mitral valve is more susceptible to
degradation and deformation.
[0007] During systolic contraction of the heart, the free margins
of the mitral leaflets and tricuspid leaflets, respectively, come
in apposition to each other and close the respective
atrial-ventricular passage. The chordae and papillary muscles hold
the leaflets in this position throughout the systole cycle to
prevent the leaflets from bulging into and opening within the
associated atrium. However, when the valve or its leaflets are
misshapen or enlarged, for example, when the annulus is dilated,
the edges of the leaflets fail to meet each other, leaving an
opening there between. This opening may involve lateral separation
of the valve leaflets and/or elevation of one valve leaflet with
respect to the other. In either case, the ineffective closure of
the valve during ventricular contraction results in regurgitation
or leakage of blood back into the atrium during ventricular
contraction, and ultimately in reduced pumping efficiency. To
compensate for such inefficiency in the mitral valve, for example,
the left ventricle must work harder to maintain the requisite
cardiac output. Overtime, this compensatory mechanism typically
results in hypertrophy of the heart followed by dilation, i.e., an
enlarged heart, which can lead to congestive heart failure.
[0008] Any one or combination of the annulus, the leaflets, the
chordae and the papillary muscles may be the cause of the mitral
and/or tricuspid insufficiency and/or regurgitation. Common
conditions or diseases to the mitral and tricuspid valves which may
result in mitral regurgitation include dilation of the annulus,
ischemic regurgitation and myxomatous degeneration of the valve
leaflet. Annular dilation typically involves the elongation or
dilation of the posterior two-thirds of the mitral valve annulus,
the section corresponding to the posterior leaflet. Ischemic
regurgitation involves a lack of blood supply to the valve tissue,
particularly the papillary muscles, due to coronary artery disease.
Myxomatous degeneration involves weakness in the leaflet structure,
leading to thinning of the tissue and loss of copation.
[0009] Various surgical techniques may be used to repair diseased
or damaged mitral and tricuspid valves. These include but are not
limited to annuloplasty (i.e., contracting the valve annulus to
restore the proper size and shape of the valve), quadrangular
resection of the leaflets (i.e., removing tissue from enlarged or
misshapen leaflets), commissurotomy (i.e., cutting the valve
commissures to separate the valve leaflets), shortening and
transposition of the chordae tendonae, reattachment of severed
chordae tendonae or papillary muscle tissue, and decalcification of
valve and annulus tissue.
[0010] Another repair technique, commonly referred to as "bow-tie"
repair, involves the edge-to-edge suturing together of the anterior
and posterior leaflets. Typically, at least one suture is placed
centrally with respect to the commissure line, creating a double
orifice valve, thereby preventing prolapse at the central portions
of the leaflets and reducing or eliminating regurgitation. The
sutures may alternatively or additionally be placed closer to the
commissures. These steps are typically performed using arrested,
open heart techniques. Following the valve repair procedure,
ultrasound is typically used to verify the repair.
[0011] Because they are performed on stopped hearts through an open
chest approach, conventional valve repair techniques may require
minimal instrumentation and time. However, because the success of
the repair can only be tested on a beating heart, the heart must be
closed up and the patient taken off the heart lung machine before
testing can be done. If the repair is determined to be inadequate,
the patient must be put back on cardiopulmonary bypass and the
heart must be reopened.
[0012] Moreover, the risks and complications associated with
open-heart surgery, which involves the use of cardiopulmonary
bypass, aortic cross-clamping and cardioplegia arrest, are well
known. The most serious risks of cardiopulmonary bypass and aortic
cross-clamping are the increase in the likelihood of bleeding and
stroke. Also, patients who undergo surgeries using cardiopulmonary
bypass often require extended hospital stays and experience lengthy
recoveries. Thus, while conventional heart valve surgery produces
beneficial results for many patients, numerous others who might
benefit from such surgery are unable or unwilling to undergo the
trauma and risks of conventional procedures.
[0013] Within recent years, minimally invasive types of procedures
for coronary artery bypass surgery have been developed which do not
require stopping the patient's heart and the use of cardiopulmonary
bypass; however, no such minimally invasive surgical procedure has
been developed for the repair of cardiac valves.
[0014] Thus, it is desirable to provide a device which, when
operatively used, involves a simplified procedure by which to
repair a cardiac valve, in particular, mitral and tricuspid valves.
For example, it would be beneficial to provide a device which, when
properly implanted, corrects a defective valve in addition to other
co-morbidities affecting proper function of the valve, obviating
the need to perform ancillary procedures to correct leaflet size
and shape, to adequately coapt the leaflets, to reattach or shorten
chordae, etc. In addition, it is desirable to provide a valve
repair procedure which requires minimal instrumentation and steps,
is easier to perform than conventional valve repair procedures and
reduces the time and cost of the procedure. Moreover, it is
desirable to provide a valve repair procedure that obviates the
need for cardiopulmonary bypass, can be performed on a beating
heart, involves endovascular or less invasive techniques, can be
performed on a patient while awake and/or in an ambulatory setting
by surgeons, cardiologists or interventionalists.
SUMMARY OF THE INVENTION
[0015] The present invention includes devices, methods and kits for
repairing cardiac valves, particularly mitral and tricuspid valves
experiencing regurgitation. The subject devices provide leaflet
grasping and fastening functions, preferably performed by a single
mechanism. The grasping function is used to apposition the valve
leaflets such that the pressure gradient between the atrium and
ventricle is optimized. The fastening function is used to
permanently secure the leaflets together at least one location
along their edges, i.e., along the commissure line. More
specifically, the subject devices include an implantable fastener
or clip having opposing jaws for grasping and temporarily and/or
permanently fastening or holding opposing leaflet edges together at
a selected point or points along the commissure line. The subject
fastening or clip devices may be made of biodegradable or
non-biodegradable materials as well as those materials which are
inert and non-thrombogenic.
[0016] The implantable fastener or clip may be provided as part of
an assembly for delivering, positioning and fastening or implanting
the fastener or clip. The subject assembly may further include one
or more means for evaluating or verifying the effectiveness of the
one or more selected points of apposition prior to permanent
placement of the fastener. Such evaluating or verification means
may include pressure monitoring probes or components for measuring
the pressures just above and just below the valve leaflets, i.e.,
in the atrium and the ventricle, respectively, and for determining
the pressure gradient or differential there between. Additionally
or alternatively, one or more flow monitoring probes may be
included for measuring the normal flow and back flow of blood
through the valve. The subject devices may further include a means
for anchoring the fastener to appropriate location on the cardiac
anatomy to prevent embolization of the fastener in case the
fastener becomes unattached from the valve leaflets.
[0017] The subject fastening or clip devices may be configured for
less invasive surgical and endovascular approaches, wherein the
implantable clip or fastener and associated delivery, positioning,
implanting and evaluation assembly are provided as part of a
cannula or catheter assembly, respectively. As such, the
implantable devices, flow probes and/or pressure monitors are
configured for delivery through a cannula or catheter, or are
themselves part of a cannula or catheter assembly.
[0018] The subject methods generally include delivering an
implantable fastener or clip to the regurgitating valve to be
repaired; monitoring the blood flow characteristics and/or pressure
gradient at the valve; grasping together the valve leaflets at a
selected point along the commissure line; determining, from
monitoring the flow and/or pressure gradient characteristics,
whether grasping at such selected point improves or optimizes the
flow characteristics and/or pressure gradient, i.e., reduces
regurgitation through the valve; and fastening the valve leaflets
at one or more selected points wherein the flow/pressure are
improved or optimized. The subject methods may further include
anchoring the fastener to an appropriate location of the cardiac
anatomy in order to prevent embolization of the fastener in case it
becomes unattached from the valve leaflets.
[0019] Such methods may further include repeating the steps of
grasping the leaflets, monitoring the blood flow characteristics
and/or pressure gradient and determining whether the flow/pressure
characteristics for each grasping step results in improvement or
optimization in such flow/pressure characteristics. The above
described steps of grasping and assessing flow and/or pressure may
be repeated until one or more suitable apposition points are found,
at which point(s) a fastener is locked into place onto the valve
leaflets. As such, such methods further include the step of
releasing the valve leaflets after the step of grasping the valve
leaflets, upon a determination that there is no or insufficient
improvement. Alternatively, the leaflets may be successively
grasped (with or without subsequent release) and fastened together
at more than one selected location, i.e., two or more of the
subject fasteners are permanently attached to the valve leaflets,
until sufficient improvement in flow and or pressure
characteristics are achieved.
[0020] Thus, a feature of the present invention is that subject
fasteners can be releasably or temporarily closed to grasp and
secure the valve leaflets at a selected apposition point, but can
also be re-opened or spread apart to release the leaflets if the
apposition point is determined not suitable, and then subsequently
reused.
[0021] The subject kits include at least one of the subject devices
and/or assemblies for carrying out the subject methods.
[0022] These and other features and advantages of the invention
will become apparent to those persons skilled in the art upon
reading the details of the subject devices and methods as more
fully described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The following drawings are provided and referred to
throughout the following description, wherein like reference
numbers refer to like components throughout the drawings:
[0024] FIG. 1A is a top view of an insufficient or defective mitral
valve having leaflets which do not coapt with each other, resulting
in regurgitation of blood from the ventricle into the atrium.
[0025] FIG. 1B is a cross-sectional view of the left side of the
human heart, including the defective or insufficient mitral valve
illustrated in FIG. 1A.
[0026] FIG. 2 is a perspective view of an embodiment of an
implantable fastener and associated delivery and grasping assembly
of the present invention.
[0027] FIG. 2A is a top view of the yoke of the assembly of FIG.
2.
[0028] FIG. 2B is side view of ajaw of the subject fastener of FIG.
2.
[0029] FIG. 3A shows the distal end of one embodiment of a fastener
delivery device of the present invention configured to accommodate
pressure and/or flow monitoring probes.
[0030] FIG. 3B is a top view of the delivery device of FIG. 3A.
[0031] FIG. 4A is a top view of the mitral valve of FIG. 1A,
wherein the valve leaflets have been fastened at a selected
apposition point along the commissure line.
[0032] FIG. 4B is a cross-sectional view of the left side of the
human heart illustrating the result of the mitral valve of FIG. 4A
having leaflets which have been fastened according to the methods
of the present invention.
[0033] FIG. 5 illustrates an embodiment of a fastener of the
present invention having an anchoring mechanism of the present
invention.
[0034] FIG. 6 is a cross-sectional view of the left side of the
human heart having mitral valve leaflets fastened with a fastener
and attached anchoring mechanism of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0035] As mentioned above, the present invention includes devices,
methods and kits for repairing cardiac valves, particularly mitral
and tricuspid valves experiencing regurgitation.
[0036] Before the present invention is described in detail, it is
to be understood that this invention is not limited to particular
embodiments and applications described, as such may, of course,
vary. For example, the following description of the invention is
primarily described in the context of mitral valve repair; however,
such description, with certain obvious modifications to the
invention, is also intended to apply to the repair of tricuspid
valves. It is also to be understood that the terminology used
herein is for the purpose of describing particular embodiments
only, and is not intended to be limiting, since the scope of the
present invention will be limited only by the appended claims.
[0037] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limit of that range and any other stated or intervening
value in that stated range is encompassed within the invention. The
upper and lower limits of these smaller ranges may independently be
included in the smaller ranges is also encompassed within the
invention, subject to any specifically excluded limit in the stated
range. Where the stated range includes one or both of the limits,
ranges excluding either both of those included limits are also
included in the invention.
[0038] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can also be used in the practice or testing of the present
invention, the preferred methods and materials are now described.
All publications mentioned herein are incorporated herein by
reference to disclose and describe the methods and/or materials in
connection with which the publications are cited.
[0039] The publications discussed herein are provided solely for
their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as an admission that
the present invention is not entitled to antedate such publication
by virtue of prior invention. Further, the dates of publication
provided may be different from the actual publication dates which
may need to be independently confirmed.
[0040] To better understand the present invention, FIGS. 1A and 1B
are provided which illustrate a defective mitral valve 2 and the
resulting effect on the functioning of the valve 2. Specifically,
FIG. 1A illustrates a defective mitral valve 2 having an annulus 4,
an anterior leaflet or cusp 6 and a posterior leaflet or cusp 8.
Mitral valve 2 suffers from valvular insufficiency as evidenced by
the gap 10 between the two leaflet edges during systole. FIG. 1B is
a cross-sectional view of the left side of a heart having a left
ventricle 12, a left atrium 14 and defective mitral valve 2
situated at the atrioventricular passageway there between. Mitral
valve 2 is tethered to papillary muscles 16 by bundles of chordae
tendinae (not shown). FIG. 1B further illustrates the effect that
the dilation of mitral valve 2 has on its ability to properly
function. Gap 10 may involve lateral separation of the valve
leaflets and/or elevation of one valve leaflet with respect to the
other. In all cases, the ineffective closure of the valve during
ventricular contraction results in regurgitation or leakage of
blood back into the atrium, thereby reducing the pumping efficiency
of the heart during systole, i.e., reducing the amount of available
oxygenated blood that is pumped by the left ventricle through the
aortic valve to the body and brain.
[0041] The various embodiments of the devices of the present
invention, which will now be described in detail, function to
correct or improve the function of such a defective mitral valve 2.
In further describing the present invention, devices of the present
invention will be described first, followed by a description of the
methods of using the subject device to temporarily or permanently
fasten or clip leaflets of a valve together. Kits which include the
subject devices will then be described.
[0042] Devices of the Present Invention
[0043] As mentioned above, the subject devices include an assembly
that is capable of grasping and fastening leaflets of a defective
valve at one or more apposition points along their edges, i.e.,
along the commissure line, either temporarily or permanently. The
subject assemblies also include delivery means such as a sheath,
e.g., a delivery catheter or cannula, and means for simultaneously
monitoring certain, relevant cardiac characteristics such as
cardiac pressure and/or flow to assess whether the fastening of the
valve leaflets at the particular apposition point improves or
optimizes blood flow and/or pressure, i.e., reduces regurgitation.
The subject devices can be used to repair a variety of cardiac
valves, wherein mitral valve repair applications will be used
herein for exemplary purposes only, and is no way intended to limit
the scope of the invention.
[0044] Referring now to FIG. 2, there is illustrated an exemplary
embodiment of a device assembly 20 of the present invention.
Assembly 20 includes an implantable fastener or clip 22 operatively
associated with a delivery sheath 40. Fastener or clip 22 includes
a jaw 24 having opposing jaw arms 26 which extend distally from a
base portion 28. Jaw arms 26 have serrations or teeth 32 located on
their inside or opposing distal surfaces for firmly but
atraumatically grasping tissue there between. In this embodiment,
teeth 30 are not designed to penetrate tissue grasped by jaw 24,
but other embodiments of the subject devices may provide
tissue-penetrating teeth. The distal ends 30 of jaws arms 26 are
preferably rounded to avoid trauma to tissue it may come in contact
with.
[0045] In their normally, biased open condition, jaw arms 26 define
an acute angle sufficient to fit about the leaflets, and typically
will be within the range from about 5.degree. to 110.degree. or
more, and more typically within the range from about 30.degree. to
60.degree.. Jaw arms 26 may alternatively be configured to be
biased in a closed position, wherein the above angle ranges would
apply to their unbiased open positions. Jaw arms 26 and have
lengths generally in the range from about 10 to 30 mm, but may be
shorter or longer depending on the application and the size of the
target heart valve being repaired. In order for jaws 24 to be
positionable about or straddle the edges of the leaflets in an open
position and to provide a sufficient grasping force in a closed
position, the separation distance between distal end 30 of jaw arms
26 is generally in the range from about 6 to 10 mm but may be
shorter or longer depending on the application and the size of the
target heart valve.
[0046] Jaw arms 26 and base portion 28 may be formed of a unitary
piece of a material that is substantially rigid, but nonetheless
provides some flexibility such that jaw arms 26 will not break when
operatively compressed together to grasp valve leaflets with a
suitable gripping force. Alternatively, jaw arms 26 may be hinged
to base portion 28 and spring-biased outward, where in this
embodiment the jaw arms are also formed of a material that is
substantially rigid, but nonetheless provides some flexibility such
that jaw arms 26 will not break when operatively compressed
together to grasp valve leaflets. In such a hinged configuration,
the material of the jaw arms 26 and the base portion 28 to which it
is hinged may be made from the same or different material, but
usually the same material.
[0047] Regardless of whether the jaw arms 26 and the base portion
28 are formed of a unitary piece of material or whether they are
separate, but hinged pieces, fastener 22 is made of any suitable
biocompatible material. Such biocompatible materials may be
permanently implantable, i.e., not biodegradable. Representative
permanently implantable materials include, but are not limited to,
plastics such as RC-1008 plastic, commonly used by those skilled in
the medical device arts, and metals or alloys thereof such as
titanium, stainless steel, aluminum, Nitinol and the like.
[0048] Fastener 22 may alternatively be made partially or wholly
from bioresorbable or biodegradable materials such that fastener 22
becomes absorbed or degrades at a rate that is sufficient to allow
the angiogenic and arteriogenic processes to form tissue adhesion
between the leaflets Suitable biodegradable materials for
fabricating fastener 22 include, but are not limited to,
polyurethane, poly (L-lactic acid), polycaprolactone, poly
(lactide-co-glycolide), poly (hydroxybutyrate), poly
(hydroxybutyrate-co-valerate), polydoxanone, polyorthoester,
polyanhydride, poly (glycololic acid), poly (D, L-lactic acid),
poly (glycololic acid-co-trimethylene carbonate), polyphosphoester,
polyphosphoester urethane, poly (amino acids), cyanoacrylates, poly
(trimethylene carbonate, poly (iminocarbonate), copoly (ether
esthers) (e.g., PEO/PLA) polyalkylene oxalates, polyphosphazenes,
as well as biomolecules such as fibrin, fibrinogen, cellulose,
starch, collagen and hyaluronic acid.
[0049] The fasteners may also have the ability to diffuse drugs or
other agents at a controllable rate at the valve leaflet coaptation
or apposition site. One or more therapeutic agents may be added to
the base material during fabrication of the fastener and/or a
coating containing such therapeutic agents may be applied to the
fastener after it has been fabricated. Suitable therapeutic agents
for use with the subject fasteners include, but are not limited to,
dexamethasone, tocopherol, dexamethasone phosphate, aspirin,
heparin, coumadin, urokinase, streptokinase and TPA, or any other
suitable thrombolytic substance to prevent thrombosis at or around
the apposition point between the valve leaflets. Such therapeutic
agents may be applied by spraying, dipping or other means. The
subject fasteners may also be seeded with endothelial cells to
promote angiogenesis between the fastener and the valve leaflet.
Still further, the subject fasteners may include materials such as
paralyne or other hydrophilic substrates that are biologically
inert and reduce surface friction, where such materials may be
applied by spraying, dipping or any other convenient means.
[0050] Furthermore, the fastener may be configured to enable
fluoroscopic visualization while delivering and operatively placing
the fasteners on the valve leaflets. Fastener 22 may comprise one
or more radio-opaque materials added to the fastener's base
material during the fabrication process or a coating containing
radio-opaque material may be applied to the fastener after it has
been fabricated. Alternatively, fastener 22 may be provided with
one or more radiopaque markers. Any suitable material capable of
imparting radio-opacity may be used, including, but not limited to,
barium sulfate, bismuth trioxide, iodine, iodide, titanium oxide,
zirconium oxide, metals such as gold, platinum, silver, tantalum,
niobium, stainless steel, and combinations thereof.
[0051] Base portion 28 has a threaded thru-hole 34 along the
central longitudinal axis of clip 22. The proximal end 38 of an
alignment pin 36 is in threaded engagement within thru-hole 34.
Threaded about alignment pin 36 is a yoke 44, best illustrated in
FIG. 2A. Yoke 44 has an elongated body portion 46 having a threaded
center thru-bore 48. The opposing end portions 50 of yoke 44 each
have a necked-downed or keyed portion 52 configured to matingly
engage with corresponding ways or grooves 54, best illustrated in
FIG. 2B, which extend lengthwise through the central portion of jaw
arms 26, respectively.
[0052] A drive rod 42 is provided which is releasably attachable to
the proximal end 38 of alignment pin 36. When in operative
engagement with alignment pin 36, drive rod 42 extends proximally
from threaded thru-hole 34 through delivery sheath 40 and
preferably beyond the proximal end (not shown) of delivery sheath
40. At its proximal end (not shown), drive rod 42 is provided with
means, e.g., a handle or a power-operated mechanism, for rotating
or turning rod 40 in clockwise and counter-clockwise directions
about its longitudinal axis. The rotation of drive rod 42 in turn
rotates alignment pin 36 in a corresponding direction along its
axis, such as the direction designated by arrow 60 of FIG. 2. Such
rotation causes yoke 44 to translate along the longitudinal axis of
alignment pin 36. As such, end portions 50 of yoke 44 are caused to
translate within grooves 54 along the respective longitudinal axes
of jaw arms 26. Rotation in one direction causes yoke 44 to
translate distally or upwards towards jaw 24, and rotation in the
opposite direction causes yoke 44 to translate proximally or
downward towards base portion 28 of fastener 22. As yoke 44 moves
distally, jaw arms 26 are caused to draw closer together until yoke
44 reaches the distal end of each groove 54 wherein respective
detents 58 are provided for locking yoke 44 permanently in place in
such distal-most position, i.e., yoke 44 may not be then be
translated in the reverse or proximal or downward direction. As
such, jaw arms 26 are permanently closed and locked in place. Drive
rod 42 may then be rotated in the opposite direction, thereby
unthreading and detaching itself from pin 36. Prior to permanently
locking yoke 44 within detents 58, however, yoke 44 may be
selectively translated proximally or distally along alignment pin
36. Proximal translation of yoke 44 causes jaw arms 26 to move
apart from each other.
[0053] As described above, device assembly 20 includes a delivery
sheath 40 for delivering fastener 22 to the appropriate area of the
heart, i.e., delivering the fastener 22 to the area of the
defective valve leaflets. Generally, sheath 40 has a proximal end,
a distal end and at least one lumen there between. FIGS. 3A and 3B
show an exemplary embodiment of a delivery sheath 40 according to
the subject invention. Delivery sheath 40 defines a lumen 62 and
usually has a tubular configuration. The dimensions and material of
such sheath 40 depend on the size of fastener 22 and the type of
approach or access route a physician employs to access the target
cardiac valve to be repaired.
[0054] For an endovascular approach, and cardiac valve applications
in particular, a catheter is used as the delivery sheath 40.
Catheters suitable for accommodating the fasteners of the present
invention include those sized generally from about 6 to 30 French,
but may be smaller or larger depending on the application and the
intended delivery path to the target heart valve. Such catheters
have lengths generally in the range from about 100 to 300 cm, but
may be shorter or longer depending on the application and the
intended delivery path to the target heart valve. As will be
explained in further detail below, it is preferable that the
internal diameter of catheter 40, i.e., the diameter of lumen 63,
be no greater than the maximum separation distance between jaw arms
26. If for practical reasons a larger diameter catheter 40 is to be
used, a secondary sheath or catheter (not shown) having a lumen
diameter which meets such requirement and is deliverable within
lumen 62 and over rod 42 may be employed.
[0055] Materials suitable for use in the subject delivery catheters
are chosen to provide the desired catheter flexibility and rigidity
in order to manipulate the catheter through a patient's
vasculature. The materials used to manufacture the catheter may
also include radio-opaque materials, where such radio-opaque
materials may include, but are not limited to, barium sulfate,
bismuth trioxide, iodine, iodide, titanium oxide, zirconium oxide,
gold, platinum, silver, tantalum, niobium, stainless steel, and
combinations thereof.
[0056] In many embodiments of the subject catheters, the catheters
are steerable so that the clinician may temporarily impart a
desired curve to the catheter from a remote location in order to be
navigated within the patient's anatomy, e.g., through the patient's
cardiovascular system. As such, drive rod 42 may have a flexible
configuration to accommodate and further facilitate such
steerability. A variety of steering mechanisms known to those of
skill in the art may be employed to impart the desired
steerability. Generally, steerable catheters includes one or more
pull wires which extend through the catheter shaft, and connect to
the catheter adjacent the distal end of the catheter at an off-axis
location. The pull wires connect to a control knob or knobs, slide
actuator, or other suitable manipulating member that is mounted in
a control handle. Representative catheters suitable for use with
the subject invention include, but are not limited to, those used
for electrophysiology, which are well known in the art.
[0057] For direct but less invasive or endoscopic approaches where
the subject devices are delivered through a trocar port placed in
the body, e.g., in the chest cavity, and delivered endoscopically
to the target location, delivery sheath 40 is preferably a cannula.
For cardiac valve applications, cannula 40 typically has a diameter
in the range from about 4 to 12 mm, and more typically from about 6
to 8 mm, and lengths typically in the range from about 10 to 30 cm,
and more typically from about 15 to 25 cm. As mentioned above with
respect to the catheter-type sheaths of the present invention, if
the lumen or internal diameter of cannula 40 is greater than that
of the maximum separation distance between jaw arms 26, a secondary
sheath (not shown), such as another cannula or a catheter, having a
smaller diameter lumen may be employed which has an internal
diameter not greater than the maximum separation distance between
jaw arms 26.
[0058] In either endovascular or endoscopic approaches, the
catheter and cannula delivery devices of the present invention may
further include additional lumens 64, as illustrated in FIGS. 3A
and 3B, for delivering ancillary instrumentation for facilitating
the implantation of the subject fasteners and clips. For example,
these additional lumens 64 may be used to deliver pressure and/or
flow monitoring probes 66a, 66b to the target valve to be repaired.
The monitoring element 68a of one probe 66a may be delivered to one
side of the valve, e.g., within the right atrium to measure blood
pressure just above the mitral valve, and a second monitoring
element of 68b of the second probe 66b may be delivered to the
other side of the valve, e.g., within the left ventricle to measure
blood pressure just below the mitral valve. Alternately, a single
probe having two spaced-apart monitoring elements may be used. With
this alternate embodiment, the probe is delivered to a point where
the distal monitoring element is positioned on the side of the
valve opposite the delivery device and the proximal monitoring
element is positioned on the side of the valve proximate the
delivery device. With either embodiment, a pressure monitoring
system (not shown) of the type known in the art external to the
patient then measures the difference between the two pressures on
opposing sides of the valve leaflets. Similarly, as mentioned
above, a monitoring element may be positioned just above the mitral
valve to measure back flow, if any, during systole. A variety of
pressure monitoring probes and flow monitoring probes, which are
known in the art, may be used with the subject invention.
Additionally, other instrumentation, such as guide wires,
endoscopes, and secondary grasping devices, may be delivered
through additional lumens 64.
[0059] Methods of the Present Invention
[0060] Also included in the present invention are methods for
repairing cardiac valves, e.g., mitral valves. In the subject
methods, leaflets of a heart valve are brought together and
temporarily grasped at a first apposition point along their edges,
i.e., along the commissure line. Once temporarily grasped, the
suitability of securing the leaflets together at the particular
coaptation or apposition point is assessed by measuring one or more
relevant characteristics related to the heart while the valve
leaflets are grasped together, such as blood flow and/or pressure,
to verify the effectiveness of fastening the leaflets together at
this apposition point. If the flow and/or pressure characteristics
are not improved or are insufficient, the leaflets are released and
then grasped again at another apposition point, where such an
apposition point is similarly evaluated for suitability. Once an
apposition point is determined suitable, the valve leaflets are
permanently fastened at that apposition point along the commissure
line. The subject steps may be repeated to successively grasp (with
or without subsequent release) and fasten together the leaflets at
more than one selected apposition point along the commissure line
until sufficient improvement in flow and/or pressure is
achieved.
[0061] Accordingly, the first steps in the subject methods is to
gain access to the area of heart which includes the valve to be
repaired and then to advance a subject fastener to the site. As
mentioned above, an endovascular approach may be used which
includes navigating a sheath such as a catheter through the
vasculature of the patient and delivering a valve repair device
there through, where the position of the catheter may be
continuously verified by fluoroscopy and/or by transesophageal
echocardiogram. Alternatively, a more direct approach may be used
wherein the heart is accessed through a trocar port placed in the
body, e.g., in the chest cavity and delivering a valve repair
device through a sheath such as a cannula positioned through the
port. Furthermore, while it is possible to perform the valve repair
procedures described herein on a stopped heart, the procedures
described herein are preferably performed on a beating heart, which
will allow certain characteristics such as blood flow and/or
pressure to be assessed during the procedure and eliminate the
risks associated with cardiopulmonary bypass.
[0062] In those embodiments employing an endovascular or
percutaneous approach to mitral valve repair using a sheath such as
a catheter to access the heart, there exists two procedures which
may be used: a retrograde approach and a transeptal approach. In
the transeptal approach, the catheter is introduced into a
patient's body percutaneously by means of a modified Seldinger
technique via the right femoral vein. By means of transesophegeal
echocardiogram, the catheter is then visualized, guided and
advanced into the inferior vena cava and into the right atrium of
the heart. The catheter then crosses the atrial septum through a
small atrial septostomy (created by cardiological techniques known
in the art) to enter the left atrium of the heart. For example, a
guide wire may be placed across the atrial septostomy and the
catheter may then be threaded along the guide wire into the left
atrium. The distal end or working end of the catheter can then be
placed or brought to rest at a predetermined position in, at, or in
proximity to the mitral valve. When performing the subject methods
to repair a tricuspid valve, there is no need for a transeptal
approach. Instead, an approach from the right atrium into the right
ventricle may be employed. In a retrograde endovascular approach, a
catheter is introduced into a patient's body via a femoral artery.
By means of transesophogeal echocardiogram visualization and
guidance, the catheter is then advanced into the aorta, crossing
the aortic valve into the left ventricle and the distal end or
working end of the catheter can then be placed or brought to rest
at a position in, at, or in proximity to the mitral valve,
preferably at the underside of the mitral valve.
[0063] In those embodiments employing a direct access approach, the
heart may be accessed by means of a traditional surgical approach,
e.g., through a sternotomy, a thoracotomy, or a sub-xyphoid
approach, or through one or more endoscopic ports positioned with
in the chest cavity, e.g., between adjacent ribs. Once access to
the heart is achieved, an entry site within a wall of the heart or
a great vessel is created. More specifically, a penetrating means
such as a trocar, obturator or guide wire or the like is used to
penetrate the myocardium. If entry through the left ventricle or
right ventricle is preferred for repair of the mitral valve and
tricuspid valve, respectively, the apex of the heart is a suitable
location to penetrate due to its resiliency to trauma. On the other
hand, the entry site may be made in the wall of the left atrium or
right atrium, respectively.
[0064] A fastener delivery sheath 40 can then be inserted through
the opening in the heart and brought to a position in, at, or in
proximity to the mitral valve, preferably the underside of the
mitral valve leaflets. Visualization and guidance of sheath 40 may
be accomplished by transesophageal echocardiogram. Once delivery
sheath 40, such as the catheters or cannulas described above, is
distally advanced and properly positioned in, at, or in proximity
to the mitral valve, the blood flow and/or pressure gradient across
the valve may be measured (although not required to be) such as by
means of the pressure/flow monitoring devices described above,
where such measurements may be used as baseline reference
measurements. In other words, these measurements, i.e., one or both
of pressure and flow measurements, may be made prior to grasping
the valve leaflets so as to determine the base line or reference
measurement of the blood flow and/or pressure gradient of the
defective valve. Another set of measurement may be then be made
after the valves have been grasped. The second measurement or sets
of measurements, i.e., post-leaflet grasping measurements, may then
be compared to the first measurement or sets of measurements, i.e.,
pre-leaflet grasping, base line, or reference measurements, to
determine the efficacy, i.e., the improvement on valve function,
e.g., the reduction in regurgitation during systole, of attaching
the valve leaflets at the selected apposition point. Such
comparison, i.e., the determination of the change in the pre- and
post-leaflet grasping measurements is performed by a flow and/or
pressure monitoring and control device, such as a microprocessor,
operatively coupled to the proximal end of the one or more flow
and/or pressure probes which extend proximally outside the
patient's body.
[0065] In those embodiments of the subject methods where baseline
measurements are performed before the valve leaflets are grasped,
delivery sheath 40 is positioned adjacent either just above or
below the leaflets of the valve to be repaired and flow and/or
pressure monitoring probes are advanced out of the delivery
catheter, i.e., out of one or more additional lumens of the
delivery device to the target valve to be repaired. For example, a
first pressure monitoring element may be advanced to one side of
the valve and a second pressure monitoring element may be advanced
to the other side of valve to measure the pressure on both sides of
the valve during systole, i.e., the pressure differential or
gradient across the valve may be measured during contraction of the
heart. As described above, the pressure monitoring elements may be
from a single probe, e.g., a single probe having spaced apart
monitoring elements, or may be from different probes. In addition
to or in place of the above described pressure measurement, a flow
measuring element may also be advanced to the site of the target
valve. More specifically, the flow probe is advanced out of the
delivery device and positioned within the left atrium just above
the valve leaflets and flow is measured during systole. As
mentioned above, these measurements may be used as baseline or
reference measurements against which to compare flow and/or
pressure measurements taken after the leaflets have been brought
together at one or more apposition points along their edges;
however these pre-leaflet grasping measurements, i.e., the baseline
measurements, may not and/or need not be performed in every
instance.
[0066] Once baseline measurements are obtained, or in the case
where baseline measurements are not first obtained, a subject valve
leaflet fastener or clip 22, as described above, is then advanced
through delivery sheath 40 to the valve to be repaired, e.g., the
mitral valve. More specifically, the subject fastener or clip 22 is
selectively positioned with respect to the valve leaflets by distal
advancement of delivery sheath 40 and/or of drive rod 42 within the
lumen of delivery sheath 40. Usually, whether employing an
endovascular, endoscopic or direct approach, fastener 22 is
delivered through the left ventricle to the underside of the
regurgitating mitral valve or, in the case of the tricuspid valve,
through the right ventricle to the underside of the regurgitating
tricuspid valve. A point of apposition, i.e., a desired fastening
point, between the leaflets is then selected. Fastener 22 is then
positioned such that the valve leaflets are positioned between
opposing teeth 32 of jaw arms 26. Preferably, this step is
performed during a systolic cycle as the leaflet cusps or edges are
closer together and, thus, easier to grasp. Sheath 40, or a
secondary sheath as discussed above, is then advanced distally over
jaw arms 26, causing jaw arms 26 to move together and thus
temporarily grasp the leaflet tissue there between.
[0067] When in a closed position, either temporarily or
permanently, jaw arms 26 maintain the valve leaflets secured
between them by exerting a gripping force on the leaflets to
sufficient to secure them between teeth 32. In many embodiments,
teeth 32 do not penetrate the jaw leaflets. However, in certain
embodiments of the subject invention, the teeth 32 include sharp
tips which can penetrate the leaflets.
[0068] Once the edges of the valve leaflets are temporarily grasped
together between teeth 32, the effectiveness of securing the
leaflets at the selected apposition point may be evaluated by
measuring the blood flow and/or pressure gradient during systole
while the valve leaflets are temporarily grasped. Similar to the
steps for measuring the baseline flow and/or pressure, a first
pressure monitoring element may be advanced to one side of the
temporarily grasped valve and a second pressure monitoring element
may be advanced to the other side of the temporarily grasped valve
to measure the pressure on both sides of the valve leaflets. As
mentioned above, in addition to or in place of the above-described
pressure measuring assessment, flow may be measured and assessed.
As such, a flow monitoring element may be positioned above the
grasped mitral valve, i.e., in the left atrium of the heart, and
blood flow may be measured during systole. Such flow/pressure
measurements may then be assessed by comparison to the baseline
measurements, if obtained previously, and/or assessed independently
based on therapeutically or clinically relevant criteria or
standards known to those skilled in the art.
[0069] Based on these assessments, it is determined whether or not
fastener 22 should be removed from or permanently fastened at the
selected apposition point. If it is determined that the flow and/or
pressure is not improved or optimized by securing the valve
leaflets at the selected apposition point, the delivery sheath 40
is moved proximally, causing jaw arms 26 to open and release the
grasp on the valve leaflets. Another apposition point is then
selected and the above-described steps for temporarily grasping and
assessing the particular apposition point is repeated until an
apposition site is determined to be suitable based on the
assessment of blood flow and/or pressure with the subject fastener
temporarily secured. The same fastener 22 may be used as described
above at these one or more successive selected points of apposition
until fastener 22 is permanently fastened to the valve
leaflets.
[0070] If, however, it is determined that the pressure and/or flow
is improved or optimized by grasping the valve leaflets at the
selected apposition point, the subject fastener 22 may then be
permanently attached to the valve leaflets at the apposition point.
While maintaining jaw arms 26 in a closed position by means of
sheath 40, drive rod 42 is rotated in the direction which will
rotate pin 36 and distally translate yoke 44 until yoke 44 is
positioned within detents 58. As such, jaw arms 26 are permanently
closed and fastener 22 is permanently fastened to the valve
leaflets. Drive rod 42 is then rotated in the opposite direction to
release fastener 22, including jaw 24 and pin 36, permanently
secured to the valve leaflets at the selected apposition point.
[0071] In addition to using transesophageal echocardiogram
techniques to visualizing and guiding the delivery sheaths 40 and
fasteners 22 of the present invention, transesophageal
echocardiogram may be employed in the subject methods to perform
the steps of determining pre- (i.e., baseline) and post-grasping
flow characteristics of the valve. The physician would then compare
the pre- and post-grasping flow characteristics to assess the
resulting improvement, if any, of placing a subject fastener at the
selected coaptation or apposition site(s).
[0072] The physician may choose to terminate the procedure upon
permanent placement of this first fastener, or elect to permanently
place one or more additional fasteners according to the above
procedures. If the physician elects to terminate the procedure, the
delivery device and the flexible rod 42 are removed from the heart
and, ultimately, the body cavity. If, however, the physician elects
to permanently place one or more additional fasteners, the subject
methods also include "re-loading" delivery sheath 40 with an
additional or subsequent subject fastener and placing the
additional fastener according to the above-described procedures.
More specifically, after permanently placing the first or previous
fastener, the delivery device may remain in place in the vicinity
of the valve while drive rod 42 is removed from the body cavity
through delivery device sheath 40. A second or subsequent fastener
22 may then be threaded onto the same drive rod 42 or otherwise
provided attached to another drive rod 42, and advanced through
delivery sheath 40 to the defective valve. The steps described
above are then repeated as appropriate.
[0073] After a subject fastener 22 has been permanently attached to
the valve leaflets, fastener 22 may be further anchored or secured
to the heart in order to minimize or eliminate the risk of
embolizing fastener 22 should it some how become unattached from
the valve leaflets. More specifically, as shown in FIG. 5, an
anchoring mechanism 70 having an anchor line 73 in the form of a
fiber, wire or suture, may be attached at one end to fastener 22
and at the other end to an anchor 74, having, for example, a clip
or button configuration. As shown in FIG. 6, anchor 74 is
configured to be placed or penetrated into or through the ventricle
wall 77 or otherwise attached to a papillary muscle of the heart
(not shown).
[0074] If for some reason fastener 22 were to become dislodged from
the leaflets, either intraoperatively or postoperatively, the
anchoring mechanism would prevent fastener 22 from traveling beyond
the left ventricle. In the endovascular methods of the present
invention, delivery sheath or catheter 40 is configured to retain
anchoring mechanism 70 during delivery and placement of a fastener
22. After permanent placement of a fastener 22, catheter 40 is
steered and manipulated to release anchor line 72 and to fix anchor
74 to an appropriate location within the heart wall. In the direct
access methods of the present invention, cannula 40 is configured
such that it retains anchoring mechanism 70 and, after permanent
placement of a fastener 22 to the leaflets of the target valve,
cannula 40 is pulled for removal through the cannula entry site
within the heart wall. Upon exiting the cannula entry site,
anchoring line 72 is pulled there through, and thereafter cannula
40 or other means delivered through cannula 40 is used to fix
anchor 74 to the heart wall. Suitable anchoring locations on the
heart wall are within or on the outside of the ventricle wall 76,
or within a papillary muscle. In either of the above methods,
anchor 74 may be alternatively fixed to the cardiac anatomy prior
to grasping the leaflets.
[0075] FIG. 4A shows mitral valve 2 of FIG. 1A after it has been
repaired according to the subject methods and with the subject
fasteners. FIG. 4A is a top view of mitral valve 2 repaired, thus
having an anterior leaflet or cusp 6 and a posterior leaflet or
cusp 8 attached at a selected apposition point 7 along the
commissure line. As shown in FIG. 4A, the gaping commissure line 10
present during systole as shown in FIG. 1A is no longer present.
FIG. 4B is a cross-sectional view of the left side of the human
heart showing leaflets of repaired mitral valve 2 of FIG. 4A
secured together at apposition point 7 with a subject fastener
22.
[0076] The subject methods may further include the absorption or
degradation of the subject fastener at a rate that is sufficient to
allow the angiogenic and arteriogenic processes to form tissue
adhesion between the leaflets. In other words, the fastener 22 may
break down after a set time period, during which time the
apposition point of the leaflets is reinforced with vascularized
tissue in-growth producing a sufficiently strong bond between the
valve leaflets. Furthermore, one or more therapeutically relevant
drugs or agents, discussed above, may be delivered or diffused to
the defective valve and more specifically to the fastened
apposition points, where such delivery or diffusion at a controlled
rate by any convenient means discussed above.
[0077] Kits of the Present Invention
[0078] Also provided by the subject invention are kits for use in
practicing the subject methods. The kits of the subject invention
at least include a subject fastener or subject assembly, as
described above. The subject kits may also include a plurality of
such subject fasteners or assemblies. The subject fasteners may be
provided with an anchoring mechanism, as described above. The
subject kits may further include one or more flow monitoring probes
and/or one or more pressure monitoring probes. Furthermore, the
subject kits may include additional instrumentation for performing
the subject methods, where such additional instrumentation may
include, but is not limited to, one or more guide wires, trocars,
guide catheters, etc. Finally, the kits may further include
instructions for using the subject fasteners and/or assemblies for
repairing cardiac valves. The instructions may be printed on a
substrate, such as paper or plastic, etc. As such, the instructions
may be present in the kits as a package insert, in the labeling of
the container of the kit or components thereof (i.e., associated
with the packaging or sub-packaging) etc. In other embodiments, the
instructions are present as an electronic storage data file present
on a suitable computer readable storage medium, e.g., CD-ROM,
diskette, etc.
[0079] It is evident from the above description and discussion that
the above described invention provides a device which, when
operatively used, involves a simplified procedure by which to a
repair cardiac valve, and, in particular, mitral and tricuspid
valves. The above described invention provides a number of
advantages, including the ability to temporarily grasp the valve
leaflets and perform blood flow and/or pressure measurements while
the leaflets are temporarily grasped to verify whether grasping the
leaflets at the particular point improves or optimizes flow and/or
pressure before permanently fastening the leaflets together. The
subject invention also effectively corrects a defective valve in
addition to other co-morbidities affecting proper function of the
valve, obviating the need to perform ancillary procedures to
correct leaflet size and shape, to reattach or shorten chordae,
etc. Furthermore, the subject methods require minimal
instrumentation and steps, is easier than conventional valve repair
procedures to perform and reduces the time and cost of the
procedure. As such, the subject invention represents a significant
contribution to the art.
[0080] All publications and patents cited in this specification are
herein incorporated by reference as if each individual publication
or patent were specifically and individually indicated to be
incorporated by reference. The citation of any publication is for
its disclosure prior to the filing date and should not be construed
as an admission that the present invention is not entitled to
antedate such publication by virtue of prior invention.
[0081] Although the foregoing invention has been described in some
detail by way of illustration and example for purposes of clarity
of understanding, it is readily apparent to those of ordinary skill
in the art in light of the teachings of this invention that certain
changes and modifications may be made thereto without departing
from the spirit or scope of the appended claims.
* * * * *